Teach you how to correctly use and maintain your pH meter in winter
Correct use and maintenance of pH electrode
The pH meter electrodes currently used in laboratories are all composite electrodes. Their advantages are that they are easy to use, are not affected by oxidizing or reducing substances, and have a fast equilibrium speed. When in use, completely remove the rubber sleeve on the liquid filling port of the pH meter electrode and the rubber sleeve on the lower end to maintain the hydraulic pressure difference of the potassium chloride solution in the electrode. The following is a brief introduction to the use and maintenance of electrodes:
1. When the composite electrode is not in use, it can be fully soaked in 3M potassium chloride solution. Do not use detergent or other absorbent reagents to wash.
2. Before use, check the bulb at the front of the glass electrode. Under normal circumstances, the electrode should be transparent without cracks; the bulb should be filled with solution and there should be no bubbles.
3. When measuring a solution with a high concentration, shorten the measurement time as much as possible and clean it carefully after use to prevent the measured liquid from adhering to the electrode and contaminating the electrode.
4. After cleaning the electrode, do not wipe the glass membrane with filter paper, but blot it dry with filter paper to avoid damaging the glass membrane, preventing cross-contamination, and affecting measurement accuracy.
5. During measurement, please note that the silver-silver chloride internal reference electrode of the electrode should be immersed in the chloride buffer solution in the bulb to avoid random jumping of numbers on the meter display. When using, be careful to shake the electrode gently a few times.
6. The electrode cannot be used in strong acid, strong alkali or other corrosive solutions.
7. It is strictly prohibited to use it in dehydrating media such as absolute ethanol, potassium dichromate, etc.
Preparation and storage of standard buffer solution
1. pH standard materials should be stored in a dry place. For example, mixed phosphate pH standard materials will deliquesce when the air humidity is high. Once deliquescence occurs, the pH standard materials cannot be used.
2. Double distilled water or deionized water should be used to prepare the pH standard solution. If it is used for 0.1 level pH meter measurement, ordinary distilled water can be used.
3. When preparing the pH standard solution, use a smaller beaker to dilute it to reduce the pH standard solution sticking to the wall of the beaker. Plastic bags or other containers storing pH standard substances should not only be poured clean, but also rinsed with distilled water several times, and then poured into the prepared pH standard solution to ensure that the prepared pH standard solution is accurate.
4. The prepared standard buffer solution can generally be stored for 2-3 months. If it is found to be turbid, moldy or precipitated, it cannot be used further.
5. The alkaline standard solution should be stored in a sealed polyethylene bottle. Prevent carbon dioxide from entering the standard solution to form carbonic acid and lower its pH value.
